1. Field of the Invention
This invention relates to an encoded film cartridge which enables an automatic camera to read film speed data for a film and more particularly to a film speed code changer which is used with the encoded film cartridge to cause the automatic camera to read different film speed data for the film so that the technique of either pushing or pulling may be used.
2. Description of the Prior Art
U.S. Pat. No. 4,714,332, entitled Film Data Reading Device, issued to Massharu Eguchi, Yoichi Tosaka, Ichiro Ohnuki, Yoshihiko Aihara and Akira Ishizaki on Dec. 22, 1987, teaches a film data reading device having a contact mechanism which reads film data by contacting a data code which is formed on a film cartridge. The contact mechanism is freely protrusible into and retractable from the loading chamber of the cartridge.
Pushing, which is described on page 417 of Encyclopedia of Photography, published by Pound Press, Inc., Crown Publishers, Inc. and the International Center of Photography in 1984, is the technique of exposing a film at higher than normal speed rating. This is most often done in order to photograph at marginal light levels, or to use a smaller aperture or a faster shutter speed than normal conditions allow. The practical effect of pushing is that the film is underexposed. Underexposure creates reduced contrast. Push processing is an extended development of a pushed film to restore the density and contrast in the middle tones and highlights that would be lost by normal development of the underexposed image. Pulling is the technique of exposing a film at lower than normal speed rating. This is most often done in order to photograph at excessive light levels, or to use a larger aperture or a slower shutter speed than normal conditions allow. The practical effect of pulling is that the film is overexposed. Pull processing is a shortened development of a pulled film to restore the density and contrast in the middletones and highlights that would be lost by normal development of the overexposed image.
U.S. Pat. No. 4,588,272, entitled Film Cartridges, Films and Camera Adapted for Use Therewith, issued to Takeo Hoda, Nobuyuki Taniguchi and Kiyoshi Seigenji on May 13, 1986, teaches a camera apparatus which is used with a film cartridge on which five first areas and a second area are formed. The APEX value Sv of the film speed of a film which is contained in the film cartridge. The five first areas have weights of 4, 2, 1, 2/3 and 1/3, respectively, and are conductive and non-conductive with the second area depending on the APEX value of the film speed. The camera apparatus includes a detector, a calculator and a circuit. The detector detects the first areas which are conductive with the second area. The calculator calculates the summation of the weights of the first areas detected by the detector and adds a predetermined constant value to the summation in order to generate a first signal directly indicative of the APEX value of the film speed which is represented by the first areas. The circuit receives the first signal.
U.S. Pat. No. 4,693,574, entitled Film Information Reading Device, issued to Ichiro Ohnuki, Yoshihiko Aihara, Yoichi Tosaka and Masaharu Eguchi on Sept. 15, 1987, teaches a reading device which reads information on the surface of a film cartridge. The reading device includes a first film information code detector and a second film information code detector. The film information code detector determines a condition of a first detecting surface of the film cartridge. The second film information code detector detects the reflection factor of a second detecting surface of the film cartridge. The information on the surface of the film cartridge includes at least information concerning the number of frames of the film and the films sensitivity. The detecting surfaces have a plurality of trains of information codes. The information codes are formed in plurality trains of patterns in the axial direction of the cartridge. The second film information code detector is arranged in a plurality of trains corresponding to the plurality of trains of information codes. The first film information code detector includes detection contact pins which are arranged to come into contact with the first detecting surface of the film cartridge. The contact pins contact an area about two times the information code area of the second detecting surface in order to detect either conductivity or con-conductivity between the contact pins.
U.S. Pat. No. 4,586,800, entitled Data Reading Device for Automatically Reading Film Cartridge Data, issued to Shinji Tominaga, Massaki Nakai, Norihiro Inoue, Akihiko Fujino, Manabu Inoue and Nobuyuki Taniguchi on May 6, 1986, teaches a data reading device for a camera which is loaded with a film cartridge having a code pattern. The code regions of the film cartridge are selectively conductive and nonconductive with a common region thereof in accordance with the film which is contained in the film cartridge. The data reading device determines whether predetermined regions of the code regions are conductive or nonconductive with the common region and reads the determination result to produce data in accordance therewith. The data reading device repeats the reading operation for a number of times at different moments and receives the plurality of data produced to produce data which is accurate with a high probability based thereon.
U.S. Pat. No. 4,783,672, entitled Method and Apparatus for Coding Photographic Materials, issued to John S. Wirtz on Nov. 8, 1988, teaches an apparatus for coding photosensitive material which includes an optical code pattern and an optical code reader. The optical code pattern is disposed on a cassette which contains a supply of photosensitive material. The optical code pattern defines a tertiary code. The optical code reader is associated with a photographic apparatus which receives the cassette. The optical code reader reads the code pattern when the cassette is inserted into the photographic apparatus to determine the type of photosensitive material which is contained in the cassette.
U.S. Pat. No. 4,490,027, entitled Magnetically Encoded Film Containers and Camera Adjusting Mechanisms Responsive Thereto, issued to Lee F. Frank and James K. Lee on Dec. 25, 1984, teaches a film container which bears magnetically encoded film information which is characterized by the information being encoded in the orientation of a macroscopic magnetic field which has strength sufficient to physically move a mechanical magnetic sensor. The encoded information is sensed either mechanically or electronically.